Given a string, your task is to count how many palindromic substrings in this string.

The substrings with different start indexes or end indexes are counted as different substrings even they consist of same characters.

Example 1:

Input: "abc"
Output: 3
Explanation: Three palindromic strings: "a", "b", "c".

Example 2:

Input: "aaa"
Output: 6
Explanation: Six palindromic strings: "a", "a", "a", "aa", "aa", "aaa".

Note:

1. The input string length won‘t exceed 1000.

找出字符串中的所有回文子串。

1、首先判斷回文

2、利用substr將字符串分割後，進行判斷統計

class Solution {
public:
    int countSubstrings(string s) {
        int res = 0;
        for
 
 (int i = 0; i < s.size(); i++) {
            for (int j = 1; j <= s.size() - i; j++) {
                if (isPalindromic(s.substr(i, j)))
                    res++;
            }
        }
        return res;
    }
    bool isPalindromic(string str) {
        int lo = 0, hi = str.size() - 1;
        
 
while (lo < hi) {
            if (str[lo] != str[hi]) {
                return false;
            }
            else {
                lo++;
                hi--;
            }
        }
        return true;
    }
};
// 204 ms

[LeetCode] Palindromic Substrings